The present invention relates to a pump including at least two pump pistons with an associated working chamber each, the working chambers being connected to suction lines by way of suction valve devices and to a joint pressure line by way of pressure valve devices.
German patent application No. 35 10 633, for example, discloses a pump of this type. This publication shows a piston pump having several cylinder-and-piston assemblies, one of which is intended to provide the suction lines of the other cylinder-and-piston assemblies with pressurized fluid. The suction valve devices of the individual cylinder-and-piston assemblies include preloaded non-return valves which will not open until a minimum pressure prevails in the suction line. In the absence of this minimum pressure, the piston cannot aspirate pressure fluid and remains in its inactive position, i.e., it does not abut on the eccentric driving it.
A disadvantage of the prior art piston pump is that it requires a pilot pressure on the suction side, to what end at least one further cylinder-and-piston assembly is required. The maximum volume flow of the pump is limited by the rate of delivery of the cylinder-and-piston assembly.
An object of the present invention is to provide a pump which is in a position to supply a great volume flow and to temporarily deactivate one or more of its cylinder-and-piston assemblies, in response to requirements.